Hryts V. Morphotropic phase transitions and relaxation states in chalcogenide crystals

The thesis is dedicated to the study of the anharmonicity of the dynamics of the crystal lattice of CuInP2S6 crystals by the methods of Raman and Brillouin light scattering spectroscopy, to the study of the dependence of the phonon spectra of such crystals on temperature and uniaxial compression, to the establishment of mechanisms of relaxation ordering in cationic sublattices of crystal structures in relation to changes in the features of ferrielectric dipole ordering and the nature of structural phase transitions on the phase diagrams temperature – pressure and temperature – chemical composition of solid solutions. Keywords: copper, indium, crystals, CuInP2S6, ferrielectrics, ferroelectrics, phase transitions, phonon spectra, Raman spectroscopy (scattering), Brillouin spectroscopy (scattering), refractive index, structural disordering, ionic conductivity.